True, an exact comparison is impossible. But a rough comparison may be useful.

And you're right, in certain situations, Rust may offer a significant advantage, e.g., security vulnerabilities. I wouldn't say that all security vulnerabilities are eliminated.

Overall, though, as you survey the IT industry in general, we can look for statistical evidence that Rust software has significantly fewer defects than, say, C++ software. Someone should compile stats for hundreds of software projects for a number of programming languages. It's perfectly doable.